Clinical significance of early diastolic notch of uterine artery Doppler velocimetry in relation to placental location

Park, Yong Won; Cho, Jae Sung; Han, Sung Sik; Kim, Jae Wook

Abstract

OBJECTIVE
Our purpose was to investigate the relation between types of early diastolic notch and placental location and to evaluate the differences in perinatal outcomes.
METHODS
We evaluated the Doppler waveform of the uterine artery in 149 pregnant women having an early diastolic notch after 26 weeks gestation, however we were unable to follow the obstetric outcomes in 20 women. Placental location was determined by transverse view of ultrasonography and classified as central and lateral placenta. The unilateral diastolic notches were divided into 3 groups depending on the placental location (ipsilateral: same side of the placenta, contralateral: opposite side of the placenta, and median: central placenta) RESULTS: In the bilateral notch group, the S/D ratio of the contralateral uterine artery was higher than the ipsilateral one(n=60, mean=3.22 Vs 2.80, p=0.0067). Of the 89 unilateral notches observed, the S/D ratio of the uterine artery in patients having early diastolic notch was higher compared to those without early diastolic notch.(t-test, mean=2.74,1.92, p=0.0001) Patients with bilateral notches were associated with poor perinatal outcomes significantly more than the patients with unilateral notches(p=0.003). Among the unilateral groups (ipsilateral: n=10, median: n=21, contralateral: n=58), there was no significant difference in perinatal outcomes.
CONCLUSION
The early diastolic notch can be observed on both or either sides of the uterine artery independent on placental location. More bilateral notches were associated with poor pregnancy outcomes than unilateral notches. The pregnancy outcomes tended to be similar in unilateral notch irrespective of placental location, but showed worse outcomes than the control group. Careful analysis of the uterine artery in nonplacental side is necessary because of the frequent appearance of early diastolic notch and higher vascular resistance.